Magic Item Creation Prerequisite Rules

Question

Under the rules for magic item creation these are the rules around prerequisites:

Note that all items have prerequisites in their descriptions. These prerequisites must be met for the item to be created. Most of the time, they take the form of spells that must be known by the item's creator (although access through another magic item or spellcaster is allowed). The DC to create a magic item increases by +5 for each prerequisite the caster does not meet. The only exception to this is the requisite item creation feat, which is mandatory. In addition, you cannot create potions, spell-trigger, or spell-completion magic items without meeting their spell prerequisites.

The bolded part is where my confusion comes in.

For example, belt of incredible dexterity states:

Construction Requirements:

Craft Wondrous Item, cat's grace

Assuming I have a scroll of cat's grace there are 2 ways to read this.

1. I have the scroll but do not know the spell thus the DC of the item is +5 for a bypassed prerequisite.

2. I have the scroll which satisfies the requirement, as per the the bold above.

Which is it in RAW and subsequently, if it is 2 doesn't that mean that I can create the item without having the requisite spells?

Answer 1

If you are not bypassing the spell prereq for the item, you are forced to 'cast' it.

http://paizo.com/prd/magicItems/magicItemCreation.html

From the creating wonderous item section (similar text can be found in almost all other feat specific sections).

If spells are involved in the prerequisites for making the item, the creator must have prepared the spells to be cast (or must know the spells, in the case of a sorcerer or bard) but need not provide any material components or focuses the spells require. The act of working on the item triggers the prepared spells, making them unavailable for casting during each day of the item's creation. (That is, those spell slots are expended from the caster's currently prepared spells, just as if they had been cast.)

so in your case, each day you spent crafting the belt, you would need to use a copy of the scroll or have someone around who can cast it for you. Otherwise, you have to add +5 to the DC of the check.

Answer 2

It's the second case. You can use a scroll or wand, an ally could cast the spell for you, and so on. Note that you must expend a scroll or charge every day that you work on the item, per the magic item description rules in the Requirements section:

A spell prerequisite may be provided by a character who has prepared the spell (or who knows the spell, in the case of a sorcerer or bard), or through the use of a spell completion or spell trigger magic item or a spell-like ability that produces the desired spell effect. For each day that passes in the creation process, the creator must expend one spell completion item or one charge from a spell trigger item if either of those objects is used to supply a prerequisite.

So yes, you can craft an item with a spell as a prerequisite without adding 5 to the DC and without knowing the spell, as long as you don't mind using a lot of scrolls or wand charges (or patient allies).